After his defeat in the Duel on Mustafar, Vader himself studied Form VII and became a master of it, at times applying elements of Juyo as part of his customized variant of Form V, employing some of its techniques when he killed the resistance fighter, Roan Lands, who was a good friend of the former Jedi Ferus Olin.
After turning to the dark side and joining the Sith, Vader continued to employ Form V. His secret apprentice, Galen Marek, was also familiar with the form, having been personally trained in its usage by Vader.
Darth Sidious was also one of the greatest and most skilled Sith swordmasters, as he has mastered all the seven lightsaber forms, all their stances and techniques and is capable of using each form equally effective ambidextrously.
During the Great Jedi Purge, the Sith Lord Darth Vader studied and mastered Form II and he often incorporated many elements of Makashi into his personalized Djem So variant, taking advantage of his cybernetically augmented strength to overcome Makashi's prime weakness.
The key architect of Vaapad was Jedi Master Mace Windu, who developed the form to address his weakness by controlling his inner darkness and channeling it into worthy ends.
Knowledge of Form VII became restricted among the Jedi Order, whose members were worried that its precepts would lead practitioners toward the dark side. In contrast, members of the Sith, such as Darth Maul, employed Juyo without reservation, as did Dark Jedi such as Galen Marek.
Among the different forms of lightsaber combat, Form VII: Juyo/Vaapad is considered to be one of the most dangerous and complex forms. It is also one of the most challenging forms to master, requiring exceptional physical and mental prowess.
Kylo Ren's lightsaber form was something of a hybrid, which blended three styles together: Djem So, Juyo, and Niman. Djem So used an irregular reverse grip and was meant for practitioners who loved fighting with a more offensive edge - a perfect fit for Ren.
Anakin Skywalker was a known user of Djem So, both during his initial stint as a Jedi and later when he subsequently fell to the Sith. The Shien variant of Form V allowed the utilization of an unconventional reverse grip, which Ahsoka Tano was known to prefer and use during battles.
Like Anakin, Darth Vader used Form V, also called Djem So, but because his mechanical suit severely limited his physical movements, he had to adapt and learn two other lightsaber disciplines.
Considered the most aggressive and unpredictable disciplines and therefore the most controversial, it was a combat style with a history of the Jedi High Council of the Jedi Order forbidding it and later allowing only select users to practice the disciplines.
Darth Traya wielded three lightsabers telekinetically against her student on Malachor V. Kreia then returned to Malachor V, where she confronted Darth Sion and forced him to submit to her will.
Form II relied on careful and controlled strikes instead of power and strength. Count Dooku was a master of this form and trained the Sith assassin Asajj Ventress in its use, though hers was less elegant than her master's. The Grand Inquisitor was a proficient Form II practitioner.
Through the Force, Yoda was considered to have mastered Form IV to its highest level. He used it in almost all of his battles, and his mastery of the style caused others to describe him as virtually unstoppable against most opponents, including Separatist battle droids, despite his small size and advanced age.
As with his clone precursors, Starkiller was programmed with the knowledge and skills of his genetic template via memory flashes. As such, he inherited the original Starkiller's preference for the Form V/Shien-style reverse grip, as well as the Form IV/Ataru and Form VI/Niman fighting styles.
Plo Koon was never anything but kind towards Anakin, showing him gratitude and respect. He also clearly appreciated Anakin taking care of Ahsoka, who Plo deeply cared aout. Luminara Unduli criticized Anakin at times, but also praised him, and respected his ability as a Jedi.
At first, Rey primarily fights with a lightsaber the same way she would have with her quarterstaff. However, after studying Luke's Jedi scripture and training with Leia, Rey probably uses Form VI: Niman, a jack-of-all-trades lightsaber form that combines different aspects of Forms I through V.
Princess Leia Organa's preferred form is never specified, but her training in both continuities indicates that she also prefers Form V. Form V, with its two sub-disciplines of Shien and Djem So, is a fast and aggressive lightsaber form, focusing on overwhelming and overpowering opponents.
However, Kylo Ren's weapon was unique and not something that's inspired by Darth Vader's lightsaber. Instead of the traditional stable red blade of Dark Lords, his was shaky, with excess frizzing and radiation that he had to add lateral vents on either side of its handle to redirect extra heat from the gem.
The lightsaber's redesign was a byproduct of the bleeding process that damaged its kyber crystal, rendering it dangerously flawed and unstable, and necessitating the lateral vents were meant to prevent the cracked kyber crystal from overloading.
Unlike other forms, Juyo encouraged Jedi to embrace their emotions and use them to fuel a relentless assault. Consequently, Form VII was outright banned by the Jedi for a long time. However, Jedi Master Mace Windu took it upon himself to refine Juyo into an offshoot known as Vaapad: the perfection of Form VII.
The black lightsaber, or Darksaber to give it its proper name, is one of the rarest lightsabers in Star Wars canon. Despite its rarity in canon, anyone who has seen the second season of The Mandalorian is likely to be familiar with the Darksaber.
